Cloud Computing: A Little Less Cloudy

By Christina McGhee, Manager/FedRAMP Technical Lead, Schellman

Today, consumers have an increasing interest in implementing cloud solutions to process and store their data. They are looking to take advantage of the benefits provided by cloud computing, including flexibility, cost savings, and availability. Fortunately, there are many cloud solutions available to consumers, touting cloud computing features such as multi-tenancy, virtualization, or increased collaboration. But is it really a cloud service?

With the rapid growth of these types of solutions, consumers and other interested organizations want to identify whether a service is actually a cloud service.

In actuality, there is such thing as a cloud service. It has a definition and we have seen federal agencies require cloud service providers to justify why their service is considered a cloud service.

The five essential cloud characteristics are based on the National Institute of Standards and Technology’s (NIST) definition of cloud computing in Special Publication (SP) 800-145. Here, NIST defines cloud computing as a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

According to NIST SP 800-145, a cloud service employs all of the following five characteristics:

1. On-demand self-service - A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider.
2. Broad network access - Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations).
3. Resource pooling - The provider’s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of resources include storage, processing, memory, and network bandwidth.
4. Rapid elasticity - Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.
5. Measured service - Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.

Whether you are a cloud service provider, consumer, or other interested party, it is important to identify how the cloud service offering meets each of the five essential characteristics. For example, cloud service providers in the FedRAMP authorization process usually document how their service meets each of the five essential cloud computing characteristics in their System Security Plan (SSP).

It goes without saying that regardless of whether or not a service meets the definition of a cloud service, the cloud service provider and consumer must always plan and prepare for the security risks associated with providing or using a the cloud service and the types of data the cloud service will consume. The cloud service provider is responsible for selecting a security program framework to implement security controls specific for cloud environments and the data protection requirements of their customers. Equally, the consumer must be fully aware of the data they plan to process and/or store with the cloud service and their responsibilities to protect that data.